Abraders, broaches, rasps and similar orthopedic surgical instruments are used in surgical procedures to modify bone structure. These instruments are adapted to cut into bone or associated softer bone-like tissues of the body to remove a portion of a bone or cartilage. Such instruments accomplish their purpose by means of tooth-like projections which wear or grind away the bone or cartilage. Typically, the tool head of these instruments is attached to a handle and perform its cutting function in a push-pull fashion.
The tool head of these instruments have cutting means formed on the cutting surface of the tool head in the form of prominences projecting from the tool head surface. The prominences or teeth act to modify the shape of a bone or cartilage when drawn across the surface to be modified.
Usually, these instruments are made of surgical steel or other metal alloys, and are designed for reuse. Reuse requires that the instrument be thoroughly cleaned and sterilized subsequent to its use, before it can be used again. It is the nature of the cutting surface on the tool head of these instruments to be covered with prominences that readily trap tissue debris during use. This tissue residue can be very difficult to remove from a tool head, especially from one with a particularly tortuous cutting surface. Even an intensive cleaning effort may not result in complete removal of all tissue residue.
Additionally, the subsequent sterilization of these tool heads does not tend to result in the removal of such debris from the cutting surface. The presence of tissue debris residue (even though sterilized) is a potential source of infectious material such as prions. A prion is a type of infectious agent made only of protein. Devices that are not properly cleaned and sterilized increase the risk of disease transfer from patient to patient. This is especially true following the emergence of certain prions that are not killed by normal hospital sterilization. Therefore, it would be beneficial to the field to have these tool heads available as disposable, one-time use items.
The field has been motivated to seek such a solution. For example, Geisser et al. (U.S. Pat. No. 5,454,815) disclose a one-time use bone rasp made of plastic. The working part of the Geisser rasp is made of a plastic material, and preferably, is provided with a hollow through bore from its proximal to its distal end. The through bore can be connected to a flush and suction line, to facilitate removal of cutting debris from the work site. However, because the tool head is made completely of plastic, and has an interior hollow through bore, there is the possibility of the tool head breaking during use. As another example, Grünig et al. (U.S. Pat. No. 6,120,508) disclose a one-time use surgical rasp having a two-piece tool head made of thin sheet metal sleeve, in the surface of which rasp teeth are formed. A plastic support is received in the sleeve, and the combination of the sleeve and plastic support are attached to a handle. Although the Grünig device may be useful for its intended purpose, it is still relatively complex, in that the tool head is a two-piece construction requiring the two mating steps: the support to the sleeve, and the combination to a handle.
Therefore, it would be beneficial to the field also to have a relatively simple, one-time use orthopedic cutting tool head made of plastic, but that has a reduced possibility of breaking during use.